In an ultrasound two-dimensional (2D) array probe, etc., a few hundred to a few thousand ultrasound transducers are used. In this case, because when the probes are connected directly to an ultrasound diagnosis apparatus, a significant number of signal lines are required and the entire cable is thickened, resulting in some troubles in the operation. Therefore, in such an ultrasound probe, a sub-array reception delay circuit with a plurality of transducers as one group (sub-array) is used. Accordingly, since it is allowed to partially apply a reception delay processing in the ultrasound probe and add for each sub-array, it is possible to reduce the number of signal lines.
On the other hand, there is a technology known as an Aperture growth that improves the reception sound field at a short distance. In the case of reception signals from a portion which is close to a body surface, there is a large difference in the delay between an ultrasound transducer that is close to the center of the aperture and an ultrasound transducer that is away from the center of the aperture. Therefore, because the delay circuit cannot allow any difference in delay, reception quality may be deteriorated. In the Aperture growth, the aperture of an ultrasound probe is reduced when reflected waves from a portion which is close to a body surface are received, and the aperture is widened as the depth is increased. Accordingly, because the ultrasound transducer that is away from the center of the aperture is not used when reflected waves from a portion which is close to the body surface are received, the delay processing based on a large delay does not need to be performed, it is possible to improve the reception sound field at short distances.
Aperture control in the ultrasound diagnosis apparatus, including the Aperture growth, is performed by a reception circuit in a main body of the ultrasound diagnosis apparatus. However, in such a constitution, if comprised such that the signals from a plurality of ultrasound transducers as a 2D array probe are added and output for each sub-array, aperture control is performed in the sub-array units. Therefore, because the Aperture growth is also performed in the sub-array units, there is a problem in that image quality is more deteriorated compared to that of an Aperture growth in the transducer units. In addition, with type of scanning to move the center of an aperture, because the position of the center of the aperture is limited in the section that is packaged as a sub-array, it was difficult to perform fine scanning. Such problems are eliminated by providing signal lines for carrying out aperture control for each ultrasound transducer and carrying out aperture control in ultrasound transducer units. However, in the case of a large number of ultrasound transducers as a 2D array probe, because there is a problem in that the number of signal lines increases and the entire cable becomes thick as described above, it is difficult to employ such a method.